This Mentored Patient-Oriented Research Career Development Award (K23) program is designed to develop expertise for becoming an independent investigator in the study of medication continuity in children with Attention-Deficit/Hyperactivity Disorder (ADHD) cared for in primary care settings. This is a critical area because despite the proven efficacy of stimulant medications to reduce ADHD symptoms, many children discontinue treatment, thereby preventing them from realizing the full therapeutic benefits of treatment and this contributes to unnecessary suffering for children and their families. The ultimate goal is to develop the expertise needed to develop evidence-based, personalized interventions to improve medication continuity among children and adolescents with ADHD. The Candidate's strong background of research and clinical training in pediatrics, education, and research provides an excellent foundation for this work. The proposed training goals include enhancing skills in the following areas: 1) biostatistical modeling with longitudinal data; 2) adherence measurement; 3) design and implementation of interventions for ADHD; 4) development of psychological, adherence, and family/self management interventions; 5) grant writing and presentation of scientific data. Achieving these training goals is essential to the Candidate's success in transitioning to independence as an investigator who pursues methodologically sound, technically feasible, and innovative approaches to intervention research in this population. The objective of the research plan is to better understand the factors that promote medication continuity in children with ADHD. A prospective, longitudinal cohort of 100 children 6-10 years old started on medicine for ADHD by their primary care doctor. The cohort will be recruited from 21 physicians in 7 practices. We will collect four waves of data over 18 months to address the following specific aims: Aim 1: Describe medication continuity in a community-based clinical cohort of children treated for ADHD. Aim 2: Identify reasons parents stop and re-start their child's medication treatment. Aim 3: Determine relationship between factors that influence family decision making and medication continuity. The Candidate plans to achieve his goal by translating knowledge gained from this study to 1) segment the population at risk for poor medication continuity and, 2) develop personalized interventions that target modifiable factors important to promote medication continuity.